I think this is a great idea. I think Steven Spilberg should direct this. I know he wanted to do (or rumor had it) Mary Poppins a while back and so if he is looking for a remake and a musical, this might be his (after he is done with the Farnsworth movie).
I think this movie can only work they way it was filmed-- on location--like the original movie. If they try to down-play that, with studio locations and shots, it real just ruin the movie and the realism to fill for any of the characters. I think one of the real reason why the original movie did so well, was the realism behind it and of course the acting. The movie and book touched so many people on every level, and if you take that away, the movie won't work.
Will Smith, Taye Diggs should be in the movie. I think that if they are cast in the right roles that everyone els who is cast will be make them shine as well. They both can sing and this could work.
As for the ladies, I would love to see any of the ladies mention in other threads. I do think JHud is great for Sophia, but for some reason I don't think she is old enough for the role, I would love to see someone like Queen Latifah, she could make it work.
Overall I think this film could work very well, as all films this would be different from the stage-version, OMG, what I would do to direct this piece...my opening of the film is to have the first number in a church. I also think it would be great to have many Celie's to see them age as well.
Anyway, I talked long enough...Oprah, if you are reading this, I would love to direct this piece.
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And seize the day,
You've been given the freedom
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To the head of the line-
To the head of the line!"
---Stephen Sondheim